阅读说明：本技术 用于三维打印机的塑型头和用于校正所述塑型头的方法 (Molding head for three-dimensional printer and method for correcting the molding head ) 是由 G·兹泰利 F·艾库维拉 于 2019-07-12 设计创作，主要内容包括：一种用于三维打印机的塑型头,包括：基体(20),其具有工作表面(22),该工作表面(22)适合于允许物体的形成和粘附；支撑设备(30),其与所述基体和用于移动所述基体(20)的移动部件(40)连接；其中支撑设备(30)是可调节的,以便改变基体(20)特别是工作表面(22)相对于移动部件(40)的方位,并且支撑设备(30)被配置成以自动化的方式在未锁定构造和锁定构造之间转换,在未锁定构造,支撑设备(30)允许基体(20)相对于移动部件(40)的方位的改变,在锁定构造,支撑设备(30)锁定由基体(20)采取的相对于移动部件(40)的方位。(A modeling head for a three-dimensional printer, comprising: a substrate (20) having a working surface (22), the working surface (22) being adapted to allow formation and adhesion of an object; a support device (30) connected to the base body and to a moving member (40) for moving the base body (20); wherein the support device (30) is adjustable so as to vary the orientation of the base body (20), in particular of the work surface (22), with respect to the mobile component (40), and the support device (30) is configured to be switched in an automated manner between an unlocked configuration, in which the support device (30) allows a variation in the orientation of the base body (20) with respect to the mobile component (40), and a locked configuration, in which the support device (30) locks the orientation assumed by the base body (20) with respect to the mobile component (40).)

1. A modeling head for a three-dimensional printer, comprising:

-a base body (20) having a working surface (22), said working surface (22) being adapted to allow the formation and adhesion of an object;

-a support device (30) connected to the base body (20);

-a movement member (40) connected to said support device (30) and having the function of operatively moving said base body (20);

wherein the support device (30) is adjustable to change the orientation of the base body (20), in particular of the work surface (22), with respect to the mobile component (40), and the support device (30) is configured to be shifted in an automated manner between an unlocked configuration, in which the support device (30) allows a change in the orientation of the base body (20) with respect to the mobile component (40), and a locked configuration, in which the support device (30) locks the orientation assumed by the base body (20) with respect to the mobile component (40);

and wherein the adjustable support device (30) comprises a plurality of levers (32), the plurality of levers (32) being connected with the base body (20), and for each lever (32) the respective clamp (33) being configured to assume a clamping configuration corresponding to the locking configuration of the adjustable support device (30) and in which the clamp (33) blocks the respective lever (32) in position, and a release state corresponding to the unlocking configuration of the adjustable support device (30), and in which the clamp (33) allows longitudinal translation of the respective lever (32) in the respective clamp (33).

2. Modelling head according to claim 1, wherein said adjustable support device (30) further comprises a support plate (31), said support plate (31) being fixed to said moving part (40) and being provided with holes (34), said rods (32) being slidably housed in said holes (34), each hole (34) being associated with a respective clamp (33) to allow or prevent translation of said rods (32) passing through said holes (34).

3. A modelling head according to claim 1 or claim 2, wherein each rod (32) is connected to the base body (20) in an adjustable and/or floating manner, preferably by means of a spherical connection, so as to absorb variations in the inclination of the working surface (22) with respect to the moving part (40).

4. A modelling head according to one or more of the preceding claims, wherein a plurality of said clamps (33) are associated with one or more respective actuators (37), said actuators (37) being configured to shift said clamps (33) between respective clamping and release configurations, said clamps (33) being preferably associated in pairs with the same actuator (36).

5. Modelling head according to claim 4, wherein said actuator (36) is of the rectilinear type, preferably a hydraulic or pneumatic piston or screw/nut electromagnetic actuator, and acts on at least one clamp (33) through a respective cam transmission element (37).

6. A modelling head as claimed in one or more of the preceding claims, wherein each said clamp (33) is defined by a part elastically deformable between the clamping configuration and the release configuration, said part being preferably a single piece, and wherein each said clamp (33) has a seat for the passage of the respective stem (32), said seat being broken laterally to allow clamping of the clamp (33) on the respective stem (32) in the clamping configuration of the clamp (33).

7. A modelling head according to one or more of the preceding claims, wherein each stem (32) is associated with a respective counteracting spring (32a) to maintain the thrust of said stem (32) in an axial direction towards an end-of-travel position of said stem (32), said counteracting spring (32a) preferably being a compression spring configured to maintain the thrust of said base body (20) away from said support device (30).

8. A modelling head according to one or more of the preceding claims, wherein said moving means (40) comprise a mechanical lift having a movable portion fixed to said support device (30), preferably to said support plate (31).

9. A modelling head according to one or more of the preceding claims, further comprising an extractor body (23), said extractor body (23) cooperating with said working surface (22), and said extractor body (23) having an external shape adapted to penetrate said working surface (22) at one or more points to promote the separation of the formed object adhered to said working surface (22) from said working surface (22).

10. A three-dimensional printer comprising:

-a cylinder (100) containing or adapted to contain a solidifiable liquid and associated with irradiation means;

-a modelling head (10) according to one or more of the preceding claims;

wherein the moving part (40) is configured to bring the base body (20) to move linearly close to or away from the bottom wall (110) of the cylinder (100).

11. Method for correcting a modelling head according to one or more of the preceding claims 1 to 9, comprising the steps of:

-arranging the modelling head (10) so that the working surface (22) is disposed in a position facing a cylinder (100), the cylinder (100) containing or being adapted to contain a liquid for three-dimensional modelling;

-bringing the supporting device (30) to the unlocked configuration;

-bringing the modelling head (10) close to the bottom (110) of the cylinder (100) until a contact is achieved in which the working surface (22) is aligned with the bottom (110) of the cylinder (100);

-switching the support device (30) to the locking configuration;

-moving the modelling head (10) away from the bottom (110) of the cylinder (100) to enable the preparation of a multilayer product of a three-dimensional model by irradiating the liquid interposed between the bottom (110) of the cylinder (100) and the work surface (22).

Technical Field

The invention relates to a modeling head for a three-dimensional printer. The invention also relates to a method for calibrating the above-mentioned modelling head.

In more detail, the present invention belongs to the field of so-called "3D printing" or "stereolithography", which, as known, is a technique capable of producing a three-dimensional object by curing and superimposing a plurality of layers obtained from a liquid resin that is easily cured under the action of an external stimulus.

Background

For various types of industries ranging from plastics to gold processing, three-dimensional printing technology can be specifically and effectively used for producing prototypes (prototypes).

According to the prior art, three-dimensional printers comprise a vat for containing the liquid resin and a modelling head equipped with a working surface, generally flat, suitable for supporting the solidified layers of the three-dimensional object to be produced. Furthermore, there are resin stimulation devices comprising a source of irradiation, typically a laser emitter or light projector (known in the technical jargon as DLP, digital light processing), capable of selectively irradiating the layer of liquid resin adjacent to the bottom of the vat in order to cure it. In more detail, each layer of the object is obtained by selectively stimulating the resin to solidify it at the points constituting the corresponding section of the object to be produced.

According to the known technique, which is very widely used, the irradiation source is located below the cylinder, the bottom of which is suitably transparent to the radiation emitted by the irradiation source itself. In this case, the three-dimensional printing process first requires that the modelling head be provided with a working surface facing downwards to face the bottom of the cylinder and be positioned at a distance from the bottom of the cylinder equal to the thickness of the first layer to be solidified. Next, a radiation source selectively irradiates the layer of liquid resin adjacent the bottom of the cylinder to cure it. In more detail, the modelling head is configured to have the solidified layer adhered thereto, while the bottom of the cylinder is conversely provided with a coating which reduces this adhesion. For each subsequent layer, the modelling head is moved away from the bottom of the cylinder, each time by an amount equal to the thickness of the layer to be produced, so as to restore the thickness of liquid resin required for processing the next layer. At the end of the production of the multilayer, the modelling head is raised, bringing the product out of the resin and retrieving it by separation from the work surface.

In this known solution, the thickness of each layer is defined by the portion of liquid resin delimited below by the bottom of the cylinder and above by the working surface of the modelling head (if the first layer) or by the last layer produced.

Thus, the production of layers with a uniform thickness (a feature necessary for the regularity of the product to be produced) requires that the working surface of the modelling head be perfectly aligned with the bottom of the cylinder containing the resin and be positioned at a precise distance (generally equal to the thickness of the first layer to be printed), generally between 10 and 200 microns, with a maximum error in terms of misalignment not greater than 5 microns.

In the state of the art, this parallelism is managed by a compensation system of the manual type, which is laborious to implement and introduces an accuracy that is not sufficient for the required standards.

From the prior art, document US2017/0173881 is known, which shows a three-dimensional printer with selectively lockable supports.

Disclosure of Invention

The technical task of the present invention is to provide a modelling head for a three-dimensional printer which overcomes the drawbacks of the prior art as described above.

In particular, it is an object of the present invention to provide a modelling head for a three-dimensional printer and a method for calibrating the same, which enable production with high precision, in particular with respect to tolerances in the thickness of the layers produced.

It is another object of the present invention to provide a modeling head for a three-dimensional printer and a method for correcting the modeling head that simplify the pre-adjustment procedure.

The technical task stated and the aims indicated are substantially achieved by a modelling head for a three-dimensional printer and a method for calibrating the same, comprising the technical features disclosed in the independent claims and/or in one or more of the dependent claims. The dependent claims correspond to further embodiments of the modelling head according to the invention.

Drawings

Additional features and advantages of the invention will become clearer from the general and therefore non-limiting description of a preferred but not exclusive embodiment of a modelling head for a three-dimensional printer and a method for calibrating the same, as illustrated in the accompanying drawings, in which:

figure 1 shows a modelling head according to the invention;

figure 2 shows the modelling head of figure 1 according to different angles;

figure 3 shows an enlarged detail of the modelling head of figure 1;

figure 4 shows a partially exploded view of the modelling head shown in figure 1;

figures 5-8 show the modelling head of figure 1 in the sequence of operating steps of the correction method according to the invention.

Detailed Description

Referring to the drawings, numeral 10 denotes a molding head for a three-dimensional printer as a whole.

With particular reference to fig. 1, 2 and 4, the modelling head 10 comprises a base body 20, a support device 30 being associated with the base body 20, the support device 30 in turn being associated with a movement member 40 (partially visible in fig. 2), the movement member 40 having the function of operatively moving the base body 20 in a vertical direction.

In more detail, the base body 20 is substantially box-shaped, hollow on the inside and provided at the bottom with a flat platform 21, the platform 21 defining a lower working surface 22, the lower working surface 22 defining a gripping area for a first layer of a multilayer product to be produced.

As shown in fig. 4, inside the base body 20 there is provided an extractor body or plate 23 actuated by a respective independent actuator, which cooperates with the work surface 22 and is profiled to penetrate the work surface 22 at one or more points to promote the separation of the object formed on or adhered to the work surface from the work surface 22. In more detail, the extractor plate 23 is provided with a projection 24, the projection 24 being configured to pass through a corresponding opening formed in the platform 21 once production has ended, so as to protrude from the bottom of the platform 21 and assist in the separation of the multilayer objects.

With the support device 30 (which can be seen for example in fig. 2), it comprises a support plate 31 and adjustment means arranged so as to connect the support plate 31 with the base body 20 and configured to allow the orientation of the base body 20, in particular of the work surface 22, to be changed with respect to the moving part 40. By means of such an adjustment device, the support device 30 can be shifted in an automated manner (i.e. in a mechanized manner, therefore by means of a mechanical actuation and transmission system) between an unlocked configuration, in which it allows the orientation of the base body 20 with respect to the mobile component 40 to be changed, and a locked configuration, in which it locks the orientation assumed by the base body 20 with respect to the mobile component 40. By means of mechanization, such a conversion is carried out almost instantaneously, in particular at the same time as the actuation of the gripper 33. The switching takes place, for example, on the basis of a user's command (pressing of a calibration start and/or stop button) or as part of a fully automated process, for example by means of a routine initiated by a processing and control unit belonging to the three-dimensional printer.

In the embodiment shown, the adjustment means comprise a plurality of levers 32, the plurality of levers 32 being connected to the base body 20, and for each lever 32a respective clamp 33 being configured to assume a clamping configuration, corresponding to the aforementioned locking configuration of the support device 30, and in which the clamp 33 locks the respective lever 32 in position, and a release configuration, corresponding to the unlocked configuration of said support device 30, and in which the clamp 33 allows a longitudinal translation of the respective lever 32 in the respective clamp 33.

To enable the rod 32 to be guided, the plate 31 is provided with holes 34 (fig. 4), the rod 32 being slidably housed inside the holes 34 and each hole being associated with a respective clamp 33 to allow or prevent translation of the rod 32 through the holes 34.

In order to absorb any misalignment (or in any case, a change in orientation) between the base 20 and the mobile part 40, each bar 32 is connected to the base 20 in an adjustable and/or floating manner, thus making it possible in this way for the bar 32 to change its inclination with respect to the base 20 and preferably also to perform a small transverse movement at the point where it engages the base 20 and/or at the junction between the bar 32 and the hole 34. Each rod 32 is preferably connected to the base body 20 by means of a spherical connection, in particular by means of a spherical end of the rod 32 inserted into a spherical accommodation formed on the base body 20.

Furthermore, each rod 32 is preferably associated with a respective reaction spring 32a (which can be seen for example in fig. 4 and 5) to maintain the rod 32 pushed in the axial direction towards the position of the end of its stroke. The counteracting spring 32a is preferably a compression spring configured to maintain the base body 20 urged away from the support device 30 and the moving member 40.

In the embodiment shown, four rods 32 and the same number of clamps 33 are provided, but the number of rods and corresponding clamps may be any (preferably a minimum number of 3, with 3 rods being used to optimize more uniform support).

The clamp 33 and its operating principle can be seen in detail in fig. 2 and 3.

In particular, each clamp 33 is defined by a member which is elastically deformable between the above-mentioned clamping configuration and release configuration. In the present embodiment, as shown in the exploded view in fig. 4, each clamp 33 has a seat (not visible in the enclosed figures) for the passage of the respective rod 32, and in particular, close to but greater than the cross-sectional dimension of the rod 32 in the release configuration, so that the rod 32 can translate freely in the clamp 33 when the rod 32 is not clamped. With reference to fig. 5, the base is broken at the side, that is to say it has a slot 35 extending from the side of the base to the outer profile of the clamp 33, to allow the clamp 33 to deform elastically at the slot 35, so as to allow the clamp 33 to clamp on the respective rod 32 in the clamping configuration of the clamp 33.

In this embodiment, each clamp 33 is made of a single piece, preferably metal.

Alternatively, instead of being defined by an elastically deformable one-piece component, each of the clamps 33 may be defined by hinged components, between which a seat for the passage of the respective lever 32 is constrained, so as to clamp or release the lever 32 itself upon command.

Advantageously, the clamps 33 are associated with respective actuators 36 (which can be seen for example in fig. 1, 2 and 4), the actuators 36 being configured to shift the clamps 33 between the respective clamping and release configurations. Each actuator 36 is preferably associated with a pair of clamps 33.

The actuator 36 is of the linear type, preferably a hydraulic or pneumatic piston or screw/nut electromagnetic actuator.

As better shown in fig. 2 or 3, the actuators 36 act on the respective clamps 33 through respective cam transmission elements 37. The transmission elements 37 are pivotally connected to the plate 31 so as to rotate under the action of the respective actuators 36 and are configured to apply pressure to the two respective clamps 33 in the clamping direction during rotation about the respective pins. In other words, the transmission element 37 is eccentrically connected (with respect to its pivot pin) to the actuator 36, and has a pair of cam surfaces, each facing a corresponding clamp 33, and in sliding contact with the corresponding clamp 33 so as to generate a change in pressing force on the clamps 33 with rotation of the transmission element 37. In this way, each actuator 36 simultaneously performs the clamping or release of two clamps 33 (even though, as previously mentioned, the inventive concept is applicable to a different number of actuators, thus for example one actuator per clamp or one actuator for all clamps).

As regards the mobile component 40, it comprises a mechanical lift (for example hydraulic or mechanical, of the type with high precision) having a movable part fixed to the support device 30 and, in particular, to the plate 31.

The mobile part 40 may be of the type described, for example, in patent application EP3205484 in the name of the applicant, on which three modelling heads are arranged, angularly spaced apart from each other by 120 °.

Fig. 5-8 illustrate a sequence of operations associated with a method for calibrating a modeling head 10 in accordance with the present invention.

Fig. 5 shows the modelling head 10 in a position facing the cylinder 100 for containing the resin and according to a general orientation misaligned with respect to the bottom 110 of the cylinder 100.

Fig. 6 shows a subsequent step of bringing the modelling head 10 into contact with the bottom 110 of the cylinder 100, in which the working surface 22 is aligned (superposed) with the bottom 110 of the cylinder 100, since the rod 32 allows absorbing the previous misalignments (different strokes of the rod 32 in the respective hole 34, compensating the inclination change).

Fig. 7 shows a subsequent step of raising the modelling head 10, for example by raising the modelling head 10 at the end of the production of the multilayer object (not shown in the drawings).

Fig. 8 shows the final step of the production process, in which the extractor body 23 is lowered so as to penetrate the platform 21 and thus enable the separation of the multilayer object previously adhered to the work surface 22.

In particular, the invention makes it possible to adjust in a fully automated manner the inclination of the platform of the modelling head, in particular of the working surface, to be perfectly aligned (parallel) with the bottom of the cylinder. This is achieved because the support device can take an unlocked configuration in which simple lowering of the head and subsequent contact with the bottom of the cylinder with the clamp released brings about automatic adaptation of the inclination of the platform. The automatic clamping of the bars by the clamps then enables the inclination assumed by the platform to be fixed, which can remain constant throughout the production of the multilayer object.

Clearly, the method has a high accuracy and a fast execution, since it is fully automated, without intervention of manual adjustment.

Furthermore, the use of the modelling head according to the invention simultaneously guarantees the determination of the absolute position of the working surface, which is necessarily located in the mechanical null of the cylinder bottom (that is to say in contact with the cylinder bottom). In other words, the present invention allows easy configuration of a so-called "mechanical zero". Finally, software is used which is able to memorize the extraction zero, so that an absolute positioning can be made for each printing routine even in the case of variations in the thickness of the platform or bottom of the cylinder.